<style>
    .footer_spac{
        text-align: center;
        position: fixed;
        bottom: 0;
        left: 0;
        z-index: 99;
        width: 100vw;
        height: 8vh;
    }
    .footer_spac>span{
        display: inline-block;
        float: left;
        font-size: 1.8rem;
        height: 8vh;
        line-height: 8vh;
        background: #ffffff;
        border-top: 0.1rem solid #dfdfdf;
    }
    .fts-back{
        width: 20%;
        border-right: 0.1rem solid #dfdfdf;
    }
    .fts-buy{
        width: 40%;
        border-right: 0.1rem solid #dfdfdf;
    }
    .fts-add-cart{
        width: 40%;
        background: #b4282d !important;
        color: #ffffff;
    }
    .brace-bottom{
        height: 8vh !important;
    }
</style>
<div class="brace-bottom"></div>
<footer id="footer_spac" class="footer_spac">
    <span class="fts-back">
        返回
    </span>
    <span class="fts-buy">
        立刻购买
    </span>
    <span class="fts-add-cart">
        加入购物车
    </span>
</footer>
<script>
    $(".fts-back").on("click", function () {
        $(".div_spac").hide()
    })
    $('.fts-buy').on('click', function () {
        if (commodity.color === 0 || commodity.info === 0 || commodity.size === 0 || commodity.number === 0) {
            $(".div_spac").show()
            return false
        }
        add_cart_buy()
    })
    $('.fts-add-cart').on('click', function () {
        if (commodity.color === 0 || commodity.info === 0 || commodity.size === 0 || commodity.number === 0) {
            alert("请选择规格数量")
            return false
        }
        add_cart()
    })
</script>